[PATCH 5/6] KVM: Add cpuid_update() callback to kvm_x86_ops

[Sheng Yang]

Sometime, we need to adjust some state in order to reflect guest CPUID
setting, e.g. if we don't expose rdtscp to guest, we won't want to enable
it on hardware. cpuid_update() is introduced for this purpose.

Also export kvm_find_cpuid_entry() for later use.

Signed-off-by: Sheng Yang <sh...@linux.intel.com>
---
 arch/x86/include/asm/kvm_host.h |    1 +
 arch/x86/kvm/svm.c              |    6 ++++++
 arch/x86/kvm/vmx.c              |    6 ++++++
 arch/x86/kvm/x86.c              |    3 +++
 4 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 4f865e8..d2a91ae 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -471,6 +471,7 @@ struct kvm_x86_ops {
        int (*hardware_setup)(void);               /* __init */
        void (*hardware_unsetup)(void);            /* __exit */
        bool (*cpu_has_accelerated_tpr)(void);
+       void (*cpuid_update)(struct kvm_vcpu *vcpu);
 
        /* Create, but do not attach this VCPU */
        struct kvm_vcpu *(*vcpu_create)(struct kvm *kvm, unsigned id);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 3de0b37..d89b0a0 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2854,6 +2854,10 @@ static u64 svm_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t 
gfn, bool is_mmio)
        return 0;
 }
 
+static void svm_cpuid_update(struct kvm_vcpu *vcpu)
+{
+}
+
 static const struct trace_print_flags svm_exit_reasons_str[] = {
        { SVM_EXIT_READ_CR0,                    "read_cr0" },
        { SVM_EXIT_READ_CR3,                    "read_cr3" },
@@ -2978,6 +2982,8 @@ static struct kvm_x86_ops svm_x86_ops = {
 
        .exit_reasons_str = svm_exit_reasons_str,
        .gb_page_enable = svm_gb_page_enable,
+
+       .cpuid_update = svm_cpuid_update,
 };
 
 static int __init svm_init(void)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 5c464ed..91dff23 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3961,6 +3961,10 @@ static bool vmx_gb_page_enable(void)
        return false;
 }
 
+static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
+{
+}
+
 static struct kvm_x86_ops vmx_x86_ops = {
        .cpu_has_kvm_support = cpu_has_kvm_support,
        .disabled_by_bios = vmx_disabled_by_bios,
@@ -4025,6 +4029,8 @@ static struct kvm_x86_ops vmx_x86_ops = {
 
        .exit_reasons_str = vmx_exit_reasons_str,
        .gb_page_enable = vmx_gb_page_enable,
+
+       .cpuid_update = vmx_cpuid_update,
 };
 
 static int __init vmx_init(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9ce7917..e16dede 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1574,6 +1574,7 @@ static int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
        cpuid_fix_nx_cap(vcpu);
        r = 0;
        kvm_apic_set_version(vcpu);
+       kvm_x86_ops->cpuid_update(vcpu);
 
 out_free:
        vfree(cpuid_entries);
@@ -1596,6 +1597,7 @@ static int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu 
*vcpu,
                goto out;
        vcpu->arch.cpuid_nent = cpuid->nent;
        kvm_apic_set_version(vcpu);
+       kvm_x86_ops->cpuid_update(vcpu);
        return 0;
 
 out:
@@ -3730,6 +3732,7 @@ struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct 
kvm_vcpu *vcpu,
        }
        return best;
 }
+EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
 
 int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)
 {
-- 
1.5.4.5

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